Cardiovascular disease is the leading cause of death in the United States. Peripheral arterial disease (PAD) pathology is commonly assumed to be vascular in nature and associated with tissue substrate delivery. Abnormal substrate utilization by skeletal muscle is seldom targeted for investigation, but may contribute equally or greater to disease pathology. The current application addresses the need for critical understanding of the specific roles of endothelial and skeletal muscle cells in the response to cardiovascular disease ischemia/hypoxia. The goal of the Mentored phase of this project is to advance the mechanistic understanding of genetic influence on PAD pathology. Previous and preliminary data support the idea that polymorphisms in the Bcl-2 associated athanogene, BAG3, regulate the response of peripheral limb tissue to ischemic/hypoxic insult. We hypothesize that BAG3 is a critical regulator of the response of both endothelial and skeletal muscle cells to ischemia and that polymorphisms in BAG3 alter its function during this insult. We propose to examine this topic in the following specific aims: 1) determine the role of BAG3 in the specific responses of skeletal muscle and endothelial cells to hypoxic insult, and 2) determine the effect of BAG3 polymorphisms on skeletal muscle and endothelial cell function in response to ischemia/hypoxic insult. This phase of the application will provide training in muscle vascular biology that will facilitate the integration of my muscle biology background into this coordinated research focus. My long-term career goal is to become a successful independent scientist investigating how the dynamic interactions between the vasculature and skeletal myocytes regulate the responses of limb muscle in both physiological and pathophysiological states, including peripheral artery disease, diabetes mellitus, and exercise. My overall hypothesis is that vascular endothelial cells and skeletal muscle interact via biological signaling cascades to propagate cellular survival and or recovery from cachectic insult. I propose to examine this topic in the Independence phase of this award in the following aim: 3) determine novel factors and signaling pathways regulating the interaction of limb muscle vasculature and skeletal myofibers during cardiovascular disease muscle and vascular remodeling. The outcomes of the research proposed in both Mentored and Independent phases will significantly advance the current knowledge of cardiovascular disease associated limb pathology.